When your having general overheating issues due to low oil or coolant/radiator failure - turning on your heater blower to full blast MAY help reduce overheating or to say the least, may increase the driving time before the vehicle overheats to un-driveable conditions. Fact or myth?

When driving up steep hills with general overheating issues OR decreased engine performance due to cylinder missfire and the like - driving at reduced speeds is better on the engine and cooling system, whereas driving with the gas pedal to the floor is bad for the engine and may result in a sudden major coolant leak. Fact or Myth?

 

well the correct answer is if your vehicle is overheating you stop immediatly, unless you are bleeding to death and the hospital is less than a bock away. In a situation where your fan has failed and you need a little extra cooling power the heater core is essentially a small radiator. but don't be a dummy stop driving if the temp is rising above normal temps.

 

why is your truck overheating?

 

Yes I had a San gauge on mine and you could watch as the temperature would drop

 

FACT-if you are overheating turn the heater on full HOT, HVAC fan on HI, this will help remove heat from the cooling system.
Also turn the a/c off as using the a/c puts extra strain on the cooling system.

FACT-driving at slower speeds will lower the strain on the engine, the harder the engine works the hotter it gets. HOWEVER driving to slow will have a reverse effect, the engine needs air flow to keep cool. Driving below 35-40 mph does not provide enough air to keep the engine cool without the added help of a cooling fan.

If you are in a general overheating situation, like climbing a big hill with the a/c on and towing a trailer in high ambient temps you would want to turn off the a/c, turn the heater on and then reduce engine power, i.e., slow down.
Keep a eye on the temp gauge, if it stays hot but does not overheat keep going.
Once you crest the hill shift into neutral and coast to a stop while increasing engine rpm to around 1,500.
Doing this will increase the coolant flow through the radiator and with no load on the engine it will not add any heat, just remove it, the engine fan will also provide increased air flow at higher rpm.
Keep in mind that if you are not pulling a trailer you can leave the engine running, the transmission in neutral and coast down the hill with the engine at idle, a/c off and heater still on.
This will remove all load from the engine and give the engine maximum air flow to cool down.
DO NOT shut the engine off while overheating unless you have complete coolant loss.
Shutting off a overheating engine removes all coolant flow, the sole purpose of the coolant is to flow through the engine block and soak up the heat.
The sole purpose of the radiator and heater core is to remove as much heat as possible.
Shut off the engine and the hot coolant just sits in one spot and the heat builds up and the engine just gets hotter and hotter and hotter.
If there is no coolant in the system then there is nothing to remove the heat anyway and continued operation of the engine will result in catastrophic failure.
If you are pulling a trailer in high ambient temps and there is a big hill coming turn off the a/c while you climb the hill, once up the hill turn the a/c back on, this will prevent most overheating under those conditions.

 

Spike covered it well. Excellent post!

I'll hit the point that I would have made, which Spike covered, which is do not abruptly stop and shut off an overheating motor unless there's no coolant left. If you're overheating at speed, then slow down. If you're overheating at idle, do what you can to get moving or get in neutral and bring the RPMs up some to increase flow of both air and fluid. Use the heater on high and A/C off to help with the shedding of heat. Once the temp comes down to a safe level, then shut it off.

 

If it is low on oil, temp is not your main concern either. If you are running it low on oil or continuing to drive it when you have a definite overheating condition that is unresolved, you are abusing it and will destoy it pretty soon anyway.

It is amazing what I see on here about people driving a vehicle way beyond the point of no return when there is a major malfunction. The longer you drive it like that, the more damage you cause.

 

When I was stationed overseas, my buddy had a Toyota something-er-other which reached the point where it wouldn't hold water/coolant anymore. Since the base was being shut down and it would have cost way more to fix than it was worth and wasn't worth shipping out of country, we drove it without water. I was surprised at how long it lasted - I think it eventually lost compression vs. throwing a rod, etc. So much for the dramatic ending he was looking for!

 

If you were in an emergency cooling situation (needed every thing you could get, stuck in the outland), turning heater on full blast, fan on high, windows down will help. You could also turn on AC, but un-hook compressor electric clutch wire. That would bring on the condenser fans only, which would also help. There might be a fuse that could be pulled to accomplish this. If really overheating (above 212 F) the condenser fans should come on anyway. Have seen posts on sites where owners have wired in a switch to force condenser fans on (like for a long hill pulling a trailer, etc.). And don't forget the case of bottled water you are hauling in the back. Not being a chemist, can't speak to the thermal properties of beer as coolant, but many people have it inside an ice chest full of ice and water. Have seen plenty of people at the drag strip use ice on the motor to cool down for the next run (radiators are uncommon in certain classes).

 

YouTube - ‪Blowing up engine!!!‬‏